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COVID-19: Lack of vitamin D is related to serious complications and the risk of death

COVID-19: Lack of vitamin D is related to serious complications and the risk of deathAccording to a retrospective study of older COVID-19 patients, lack of vitamin D is linked to serious lung symptoms, longer disease duration, and increased risk of death. The problem is made worse by the fact that vitamin D deficiencies are so common among older people, nursing home residents, and exposed population groups. According to a new study published in Nutrients, doctors and scientists advise governments worldwide to include vitamin D supplementation in their campaigns and strategies for fighting COVID-19 and mutations of the virus. The study supports earlier research showing that lack of vitamin D is a risk factor for all age groups. The question is how much vitamin D does one need to have optimal levels of the nutrient in the blood?

The aim of the new study was to demonstrate if blood levels of vitamin D are linked to clinical parameters in older hospitalized COVID-19 patients. A total of 66 COVID-19 patients with an average age of 76 years took part in the study. They were compared to a healthy control group that was matched for age and gender. The scientists measured the patients’ lung function, blood levels of vitamin D, and levels of CRP (C-reactive protein) that is an inflammation marker. The scientists also looked at how long the patients were hospitalized and how long they had symptoms.
They found that patients hospitalized with COVID-10 had significantly lower levels of vitamin D in their blood compared with the healthy controls. There was also a significant correlation between low blood levels of vitamin D and levels of CRP, which serves to show that lack of vitamin D increases the unwanted and potentially violent inflammation that is one of the main reasons why COVID-19 infections suddenly become complicated and potentially life-threatening.
What the scientists also observed was a direct link between low levels of vitamin D in the blood and serious lung complications.
Finally, the researchers found that having low levels of vitamin D in the blood was linked to prolonged hospitalization and an increased risk of death. They conclude that lack of vitamin D is associated with serious lung complications, prolonged hospitalization, and an increased of dying of the COVID-19 infection. Their study is published in Nutrients.
Because the study only included a limited number of patients, the researchers also refer to other studies were vitamin D deficiency was shown to increase the risk of infection, serious complications, and an increased risk of dying of COVID-19.
It is already known that low vitamin D status is common among people of color, overweight individuals, diabetics, patients with elevated blood pressure, and nursing home residents. The widespread vitamin D deficiency may explain why seemingly healthy people develop serious complications from a COVID-19 infection. You don’t notice if you lack vitamin D, but the immune system is unable to function normally when levels of the nutrient are too low.

The body’s endogenous synthesis of vitamin D is impaired by factors such as:

  • Winter
  • Spending too much time indoors
  • Ageing
  • Having dark skin
  • Being overweight
  • Having diabetes
  • Using sun cream with factor

How vitamin D protects against COVID-19 infection and complications

COVID-19 attacks different cells with ACE2 receptors on their surface. ACE2 is a central component of RAS (renin-angiotensin system) that controls blood pressure by regulating the amount of fluid in the body.
An infection usually starts by virus infecting cells in the nose via the ACE2 receptors. A properly functioning immune system can easily defeat the virus and prevent it from replicating and spreading. However, if the immune system does not function optimally the COVID-19 virus can replicate in the nose cells and spread to other cells with ACE2 receptors in the airways, the arteries, the heart, the intestines, and the kidneys. This explains some of the symptoms that occur when these organs and tissues are infected. COVID-19 does not only attack cells with ACE2 receptors. It is also able to upregulate ACE2 receptors in the lungs and circulatory system, causing everything to go haywire. The virus spreads violently and RAS gets entirely out of control. At the same time there is a risk that the immune defense overreacts with a cytokine storm and hyperinflammation that destroys healthy tissue.
It is the capacity of the immune defense that determines whether we reject COVID-19, develop a mild infection, or sustain life-threatening complications.
Vitamin D supports the immune system and circulatory system in numerous ways through its role in:

  • Regulating the innate immune defense that is designed to defeat most infections
  • Regulating the adaptive immune defense, including T cells, that enhance the immune system’s attacks
  • Regulating the communication between immune cells and the maturation of T cells
  • Regulating the T cells to prevent cytokine storm and hyperinflammation
  • Regulating the RAS (renin-angiotensin system) that is crucial for the circulatory system and the kidneys. RAS is affected in complicated cases of COVID-19
  • Counteracting microclots that contribute to lung complications and death

Important message: Vitamin D supplements are relevant for all age groups

Many studies have been made. The new study is the most recent one to link low vitamin D status to COVID-19 infection risk and disease severity. Many scientists and medical experts have urged world leaders to include vitamin D supplements as part of their strategy for fighting COVID-19
The problem is that the actual need for vitamin D is a lot higher than the official recommendations, at least if the goal is to optimize levels of the nutrient in the blood. Factors such as eating habits, genetic variations, sun exposure, age, skin type, BMI, and chronic diseases can all affect individual needs. A blood sample can easily determine if you have enough vitamin D in your blood. Still, one must take other factors into account such as the time of year. People normally lack vitamin D during the winter period and in the early spring where the sun is too weak to enable vitamin D synthesis in the skin.
You can buy high-dosed vitamin D supplements (20-80 micrograms) on the market. Vitamin D is lipid-soluble so you get the best absorption of the nutrient by taking it in soft capsules where it is mixed with oil. EU’s Scientific Committee on Food has set 100 micrograms per day as the safe upper intake level for vitamin D for children aged 11 year and older and for adults.

Blood levels of vitamin D

  • Blood levels of vitamin D are categorized as deficiency (below 30 nmol/L), insufficiency (30-50 nmol/L), and sufficiency (higher than 50 nmol/L).
  • Several experts believe that the optimal level is around 75-100 nmol/L


Cutolo M et al. Vitamin D and Lung Outcomes in Elderly COVID-19 Patients. Nutrients 2021

Nikki Hancocks. Study backs link between Vitamin D and COVID-19 severity. 2021

Liji Thomas. Vitamin D deficiency associated with higher risk of COVID-19 hospitalization. News Medical Life Sciences. Jan 21, 2021

Lobachevsky University. Scientists have identified the role of chronic inflammation as the cause of accelerating aging. Medical Xpress. 2020

Hutchings, N. et al. Patients hospitalized with COVID-19 have low levels of 25-hydroxyvitamin D. Endocrine.

Michael R Garvin et al. A mechanistic model and therapeutic interventions for COVID-19 involving a RAS-mediated bradykinin storm. eLife Jul 7, 202

JoAnn E. Manson. Commentary. Eliminating vitamin D deficiency during the COVID-19 pandemic. A call to action. Metabolism Clinical and Experimental. July 23, 2020

Northwestern University. Vitamin D levels appear to play role in COVID-19 mortality rates. Science Daily. May 2020

Ali Daneshkhah et al. The Possible Role of Vitamin D in Suppressing Cytokine Storm and Associated Mortality in COVID-19 Patients. medRxiv April 30, 2020

Eamon Laird, Rose Anne Kenny. Vitamin D deficiency in Ireland – implications for COVID 19. Results from the Irish Longitudinal Study on Ageing (TILDA) April 2020

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